LOCATION GAVINS SD+NEEstablished Series
TAXONOMIC CLASS: Loamy, carbonatic, mesic, shallow Typic
Ustorthents
TYPICAL PEDON: Gavins silt loam. (Colors are for dry soil unless otherwise stated.)
A--0 to 4 inches; dark gray (10YR 4/1) silt loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft; very friable; abundant coarse and fine roots; common siltstone fragments; very dark brown (10YR 2/2) coatings on the faces of some peds; strong effervescence (45 percent calcium carbonate); neutral; clear smooth boundary. (3 to 5 inches thick)
AC--4 to 10 inches; pale brown (10YR 6/3) silt loam, dark brown (10YR 4/3) moist; very weak medium prismatic structure parting to weak fine subangular blocky; soft, very friable; many fine roots; common siltstone fragments; violent effervescence (60 percent calcium carbonate); neutral; gradual wavy boundary. (5 to 10 inches thick)
C--10 to 18 inches; very pale brown (10YR 7/3) silt loam, yellowish brown (10YR 5/4) moist; massive; soft, very friable; many fine roots; many siltstone fragments; violent effervescence (80 percent calcium carbonate); neutral; diffuse irregular boundary. (4 to 8 inches thick)
Cr--18 to 40 inches; very pale brown (10YR 7/4) siltstone, very pale brown (10YR 7/4) moist; thin layers of gypsum between bedding planes; violent effervescence (90 percent calcium carbonate); slightly alkaline.
TYPE LOCATION: Davison County, South Dakota; about 5 miles south of Betts; 1540 feet south and 524 feet east of the northwest corner of sec. 22, T. 102 N., R. 61 W.
RANGE IN CHARACTERISTICS: Depth to siltstone is 10 to 20 inches. In some pedons, the upper 10 inches is a thin mantle of glacial till or local alluvium. Siltstone fragments are in all parts of the solum. Small igneous rocks are in the upper part of some pedons. The control section typically is silt loam or silty clay loam but in some pedons it is loam that averages from 20 to 30 percent clay and less than 15 percent fine or coarser sand. The profile ranges from neutral to moderately alkaline throughout.
The A horizon has value of 3 to 5 and 2 or 3 moist, and chroma of 1 or 2. It is loam, silt loam or silty clay loam.
The AC horizon is 10YR or 2.5Y hue, values of 5 to 7 and 4 to 6 moist, and chroma of 2 to 4. It is loam, silt loam or silty clay loam. Calcium carbonate equivalent ranges from 40 to 80 percent.
The C horizon has hue of 10YR, 2.5Y, or 5Y; value of 5 to 8 and 5 to 7 moist; and chroma of 1 to 5. Few or common accumulations of gypsum are in some pedons. Calcium carbonate equivalent ranges from 50 to 90 percent.
The Cr horizon is soft siltstone and is easily penetrated but becomes hard when exposed to air. Seams of gypsum ranging from 1/4 to as much as 3/4 inch in thickness occur between fracture planes.
COMPETING SERIES: This is the only series in the family.
GEOGRAPHIC SETTING: Gavins soils are undulating to steep or convex ridges bordering deeply entrenched streams and larger drainages. Slope gradients range from 6 to 60 percent. These soils formed in sediments weathered from soft siltstone high in carbonates. The mean annual temperature ranges from 45 to 50 degrees F, and mean annual precipitation ranges from 17 to 25 inches. Growing season is about 130 to 155 days; average growing season precipitation ranges from 15 to 20 inches; and growing degree days are about 2700 to 3500.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Betts, Redstoe, and Sansarc soils. Betts soils do not have paralithic bedrock within 40 inches and Sansarc soils have a fine textured control section. They are on similar landscapes. Redstoe soils are 20 to 40 inches to siltstone, have mollic epipedons, and are on less sloping landscapes.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is high or very high. Permeability is moderate above the bedrock.
USE AND VEGETATION: Used almost exclusively as rangeland. Native vegetation is mainly little bluestem, sideoats grama, blue grama, western wheatgrass, big bluestem, prairie dropseed, green needlegrass, sedges, and forbs.
DISTRIBUTION AND EXTENT: Southeastern South Dakota and northeastern Nebraska. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Davison County, South Dakota, 1971.